1. Field of the Invention
The present invention relates to an aromatic nitrogen-containing heterocyclic azo dye, a coloring composition comprising the azo dye for use in image formation, etc., and an ink for ink jet recording, an ink jet recording method, a heat-sensitive recording material, a color toner and a color filter using the same.
2. Background of the Related Art
In recent years, as an image recording material there has been mainly used a material for forming a color image. In some detail, recording materials for ink jet recording, heat-sensitive transferring type recording materials, electrophotographic recording materials, transferring silver halide light-sensitive materials, printing inks, recording pens, etc. have been widely used. A color filter is used to record and reproduce a color image in such picture-taking apparatus as imaging devices (e.g., CCD) and displays such as LCD and PDP.
These color image recording materials and color filters comprise coloring agents (dye or pigment) of so-called additive or subtractive primaries to reproduce or record a full-color image. However, it is the status of quo that there is no fast coloring agents that have absorption characteristics allowing the realization of desirable color reproduction region and can withstand various working and atmospheric conditions. It has thus been keenly desired to provide improved coloring agents.
The ink jet recording method has been rapidly spread and further developed because it requires inexpensive materials, enables high speed recording, generates little noises and allows easy color recording.
Examples of the ink jet recording method include continuous process involving continuous flying of droplets and on-demand process involving flying of droplets according to image data signal. Examples of ink ejection method include a method which allows a piezoelectric element to give pressure that causes a droplet to be ejected, a method which comprises heating the ink to generate bubbles, causing a droplet to be ejected, a method involving the use of ultrasonic wave, and a method which uses electrostatic force to suck and discharge a droplet. As inks for these ink jet recording methods there are used aqueous inks, oil-based inks and solid (melt type) inks.
The dyes to be incorporated in these inks for ink jet recording are required to exhibit a high solubility or dispersibility in solvents, allow a high density recording and have a good hue and a good fastness to light, heat and active gases in the atmosphere (oxidizing gases such as NOx and ozone and SOx), an excellent fastness to water and chemicals, a good fixability to image-receiving materials giving difficulty in running, an excellent preservability as inks, no toxicity and a high purity and be available at a low cost. However, it is extremely difficult to seek coloring agents meeting these requirements to a high extent. In particular, it has been keenly desired to provide a coloring agent which exhibits a good hue as a hue for compensating that of black dyes on the long wavelength side and a good fastness to light, moisture and heat, particularly to oxidizing gases such as ozone in the atmosphere when printed on an image-receiving material having an ink-receiving layer containing a porous white inorganic particulate material.
Color copiers and color laser printers utilizing electrophotographic process normally use toners having a coloring agent dispersed in a particulate resin. Color toners are required to have absorption characteristics realizing desirable color reproduction region, particularly a high light transmittance (transparency) required in the use with over head projector (hereinafter referred to as “OHP”) and various fastnesses under actual atmospheric conditions. Toners having a pigment dispersed in a particulate material as a coloring agent are disclosed in JP-A-62-157051, JP-A-62-255956, JP-A-6-118715, etc. These toners are excellent in light-resistance but are disadvantageous in that they are insoluble and thus can be easily agglomerated, causing deterioration of transparency and change of hue of transmitted light. On the other hand, toners comprising a dye as a coloring agent are disclosed in JP-A-3-276161, JP-A-7-209912, JP-A-8-123085, etc. Unlike the aforementioned toners, these toners have a high transparency and show no hue change but are disadvantageous in light-resistance.
The heat-sensitive recording method is advantageous in that it employs a small-sized apparatus realizing cost reduction, allows easy operation and maintenance and requires reduced running cost. Coloring agents for use in heat-sensitive recording are required to have absorption characteristics realizing desirable color reproduction region, accomplish both desired heat transferability and fixability after transfer at the same time, exhibit a high thermal stability and provide an image with various fastnesses. However, there are no known coloring agents which can meet all these requirements. For example, a heat-sensitive recording material and an image-forming method involving the chelation of a heat-diffusive dye with a transition metal ion previously incorporated in an image-recording material for the purpose of improving fixability and light-resistance are proposed in JP-A-60-2398, etc. However, the aforementioned proposal is disadvantageous in that it produces a chelate dye having unsatisfactory absorption characteristics and requires the use of transition metals that cause environmental problems.
The color filter is required to have a high transparency. Thus, in order to prepare the color filter, a so-called dyeing method involving the coloring with a dye has been practiced. A color filter can be produced, e.g., by successively repeating for all the filter colors a step which comprises subjecting a dyable photoresist to pattern wise exposure and development to form a pattern, and then dyeing the pattern with a dye of the filter color. Besides the dyeing method, a method involving the use of a positive resist as disclosed in U.S. Pat. No. 4,808,501 and JP-A-6-35182 can be employed to produce a color filter. These methods require the use of a dye and thus can provide a color filter with a high transmittance and excellent optical characteristics but are limited in light-resistance, heat resistance, etc. It has thus been desired to develop a coloring agent having an excellent resistance to various conditions and a high transparency. On the other hand, methods involving the use of an organic pigment having excellent light-resistance and heat resistance instead of dye have been widely known. However, a color filer comprising a pigment can difficultly exhibit optical properties as obtained with dyes.
The coloring agents for use in the aforementioned various purposes have requirements common to all. In some detail, these coloring agents are required to have absorption characteristics desirable for color reproduction, good fastness to actual atmospheric conditions such as light, heat, moisture and oxidizing gases such as ozone and chemicals such as sulfite gas, a great molar absorptivity, etc.
As coupling components of azo dye there have heretofore been widely used phenol, naphthol, aniline, etc. As azo dyes having a good hue obtained by these coupling components there are known those disclosed in JP-A-11-209673, Japanese Patent 3,020,660, etc. However, these dyes are disadvantageous in that they have deteriorated light-fastness.
As an approach for eliminating these problems there has been recently disclosed a coloring agent having a good hue and enhanced light-fastness in JP-A-2001-335714. However, all the coloring agents known in these patents or specifications leave much to be desired in fastness to oxidizing gases such as ozone. In order to develop a coloring agent fast to oxidizing gases such as ozone, the present inventors have worked out an idea that nitrogen-containing heterocyclic compounds should be used as coupling components instead of related art coupling components such as phenol, naphthol and aniline. As patent applications concerning azo dyes comprising pyridine and pyrazine as coupling components there have been known JP-A-49-74718, European Patent 23,309, German Patent 2,513,949, German Patent 2,832,020, Patent German Patent 2,525,505, etc. However, it was not known in those days that these dyes are used in image formation processes such as ink jet recording. Further, the azo dyes disclosed in these patents leave something to be desired in fastness to light, heat, moisture and ambient active gases such as ozone. Moreover, aza acridone skeletons are known, but disazo dyes comprising this skeleton as a coupler have never been known.